Gamma radiation source and method for the treatment of sewage

ABSTRACT

A method is disclosed for the treatment of contaminated water (sewage) by the gamma rays from fission byproduct waste so as to kill bacteria and/or degrade chemical waste in the contaminated water. The fission byproduct waste is encapsulated in a leachresistant glass or ceramic product to form a radiation source. The radiation source is held by a holder inside a casing containing coolant. The source, holder, casing and coolant form a natural convection cell for the dissipation of heat. The casing with contents form radiation cells which may be interlocked into rows to form channels. The rows of cells may be fitted with guide vanes to give a generally helical motion and mixing of the contaminated water so as to ensure uniform irradiation of the water. The channels may be cleaned by high velocity water jets. As a result, a treatment plant may be designed and built so that sewage receives at least 0.14 megarads of radiation, which is sufficient to kill at least 99.99 percent of the Escherichia Coli bacteria degrade many chemical compounds, especially the benzyl sulfonate detergents, and accelerate sedimentation.

United States Patent 721 Inventors Flore n. Miraldl 2660 Edgehlll Rd.,Cleveland Heights, Ohio 44106; Edward J. Morgan, 19713 Shakerw'ood Rd.,Warrensville Heights, Ohio 44122 Sewage and Industrial Wastes; Vol. 25;No. II; Dunn; pgs. 1277- 1281; November, 1953; 210-64 Journal Am. WaterWorks Association; Vol. 48; No. ll; Lowe et al.; Pgs. i363- l372;November, 1956; 210-64 Primary'EJmminer Archie R. Borchelt AssistantExaminer-A. L. Birch An0rney-- Fay, Sharpe and Mulholland ABSTRACT: Amethod is disclosed for the treatment of contaminated water (sewage) bythe gamma rays from fission byproduct waste so as to kill bacteriaand/or degrade chemical waste in the contaminated water. The fissionbyproduct waste is encapsulated in a leach-resistant glass or ceramicproduct to form a radiation source. The radiation source is held by aholder inside a casing containing coolant. The source, holder, casingand coolant form a natural convection cell for the dissipation of heat.The casing with contents form radiation cells which may be interlockedinto rows to form channels. The rows of cells may be fitted with guidevanes to give a generally helical motion and mixing of the contaminatedwater so as to ensure uniform irradiation of the water. The channels maybe cleaned by high velocity water jets. As a result, a treatment plantmay be designed and built so that sewage receives at least 0.14 megaradsof radiation, which is sufiicient to kill at least 99.99 percent of theEscherichia Coli bacteria degrade many chemical compounds, especiallythe benzyl sulfonate detergents, and accelerate sedimentation.

I II!!! 1/ IIIIIIII/II/ II Ill/l] III PATENTEDSEP 7am 3.603.788

sum 2 [IF 5 FIG. 4

FIG. 5

INVENTORS. FLORO D. MIRALDI 8 B EDWARD J. MORGAN 444,, 5 2 Maw/4ATTORNEYS PATENTEDSEP 7|9?| 3.603788 ATTORNEYS PATENTEUSEP 7l97| 35037SHEET 5 BF 5 FIG. u

liar fi H3 r k I FIG. I2 202 gf fff INVENTORS.

FLORO D. MIRALDI 8 BYEDWARD J. MORGAN 464,, m MW ATTORNEYS GAMMARADIATION SOURCE AND METHOD FOR THE TREATMENT OF SEWAGE BACKGROUND OFTHE INVENTION In present practice, bacteria in sewage are normallykilled by chlorination, but the system is expensive, the chlorine itselfcontaminates the water, and, as a result, the chlorination is often usedin the hot part of the year. It is already known that gamma radiationcan be used to treat sewage, but, until now, no economically feasiblesystem has been proposed. The purpose of the present invention is to usethe gamma radiation from fission byproduct waste to treat sewage in aneconomically feasible system.

Previous research has shown that E. Coli bacteria can be killed byradiation in the amount of 99.99 percent with a dosage of about 0.14megarads. Radiation also degrades synthetic detergents and othercompounds to whatever degree is desired.

In addition, we have found that various organic and inorganic materialsthat are suspended solid components in water, generally of colloidalproportion, may be coagulated. Some of these suspended solids consist ofvarious organic matter which call for a biological oxygen demand fordegradation. Frequently, these components will collect and settle andcan be separated from the water, which is then returned to its source.By the use of radiation, we can increase the sedimentation of thesuspended sold components because radiation can cause an agglomerationof the pollution particles which then become sufficiently enlarged tosettle. It is also obvious that with a source of radiation no additionalcontaminants or materials need to be added to the effluent, and wethereby avoid one source problems.

In this invention, we use the gamma radiation from fission byproductwaste which is available in large quantities and is currently stored inthe ground. bThese fission byproduct wastes are currently a financialburden on the United States Government since safe storage is expensive.It is considered that our particular use of fission product waste wouldtake a large fraction of this kind of material and relieve a part of thestorage burden. At the present time in the state of the art, some of thefission product waste has been handled by encapsulating in one form oranother, and by mixing the wastes with chemicals to form a ceramic orglasslike product and, thus, a material impregnated throughout with alarge amount of waste. This impregnation technique per se is describedin Watson, L. C. et al., The Disposal of Fission Products in Glass,Second United Nations Conference on Peaceful Uses of Atomic Energy,Geneva, Switzerland, 1958, Volume 18, page 19.

This invention describes an economically feasible sewage treatmentsystem in which is used fission byproduct wastes which have beenencapsulated in a leach-resistant glass or ceramic product.

SUMMARY OF THE INVENTION An object of this invention is to provide asystem for the treatment of sewage and for treating large quantities ofwater with a radiation source by moving one with respect to another.

Another object of this invention is to provide a design of a sewagetreatment system using fission product waste as a radiation source sothat large quantities of sewage may be treated economically withradiation.

A further object of this invention is to provide a type of radiationcell that may be used in greatnumbers for treatment of sewage, with thecell encompassing an encapsulated or impregnated source of high-energyelectromagnetic radiation, a suitable holder therefor and a coolantsurrounding the radiation'source, all contained in a casing so that theflow of sewage is not in direct contact with the radiation source but isinsulated therefrom by the casing and the coolant layer.

In the treatment of sewage containing human fecal matter, we propose totreat said sewage to kill a high percentage (of the order 99.99 percent)of the Escherichia Coli bacteria by exposing the sewage to a source ofelectromagnetic radiation from fission product waste products. The majorportion of the activity is due to the isotopes strontium-yttrium,cesium-barium and promethium, which may account for as much as 87percent of the total activity. Since the range of beta rays in materialis very small, irradiation of the sewage would be primarily accomplishedby the gammas emitted by barium 137, which is the daughter of cesium andaccounts for 14 percent of the total activity. These fission wasteproducts are impregnated in a solid such as nepheline syenite glass orother ceramic and put in the form of a brick, rod, ball, bead or othershape. The source is placed in an appropriate casing with coolantforming a convection cell which will permit efficient cooling andseparate the source from the stream of sewage passing on the outside ofthe convection cell. The radiation source and cell may be employed insubstantial numbers to expose the sewage to the radiation so that alethal dose of radiation treats substantially all (greater than 99percent) of the Escherichia Coli bacteria and degrades percent of thebenzyl sulfonate synthetic detergents.

In the drawings:

FIG. 1 is a vertical elevational view of a radiation cell consisting ofthe source, the source holders, and the outer casing therefor;

FIG. 2 is a vertical cross-sectional view of FIG. 1;

FIG. 3 is a horizontal cross-sectional view along the lines 3-3 of FIG.I; 7

FIG. 4 is a sectional view of a radiation cell using pebble orball-shaped radiation elements;

FIG. 5 is a vertical cross-sectional view of a sewage treat ment systemshowing five radiation elements with their associated guide vanes in theflow path of the sewage;

FIG. 6 is a side elevational view of a series of radiation cells of FIG.I and 4 along with the guide vanes to provide circulation of the sewagein a helical manner around each row of cells to provide proper mixing ofthe sewage for substantially uniform irradiation;

FIG. 7 is a cross-sectional plan view of the radiation cells of FIG. 6;

FIG. 8 is a diagram of the relative flux distribution from a uniformplane slab of radiating material showing the manner which the fluxdistribution exponentially declines with respect to distance from theslab;

FIG. 9 is a side elevational view of a series of radiation cells of FIG.1 and 4, along the airfoil type vanes as an alternate method to thatshown in FIG. 6 to provide circulation of the sewage in a helical manneraround each row of cells to provide mixing of the sewage forsubstantially uniform irradiation;

FIG. 10 is a cross-sectional plan view of the radiation cells of FIG. 9;

FIG. 11 is a side elevational view of a series of radiation cells ofFIG. 1 and 4 along with a guide vane arrangement, which is an alternateto the systems of FIG. 6 or FIG. 9, to provide circulation of the sewagein a helical manner around each row of cells to provide mixing of thesewage for substantially uniform irradiation;

FIG. 12 is a cross-sectional plan view of the system FIG. 11; and

FIG. 13 is a cross-sectional plan view of the guide vane portion of thesystem of FIG. 1 1.

Currently the sewage treatment practice calls for a measurement of theEscherichia Coli, commonly known as, E. Coli, which is used as thereference standard for sewage purification. The E. Coli are abundantlypresent in human fecal matter and tend to be one of the more resistantto treatment. The table below presents the radiation sensitivity of E.Coli. Present sewage treatment practice with chlorine results in abacteria removal of greater than 99 percent. We treat the sewage in themanner described in this application to remove 99.99 percent of thebacteria at a treatment of 0. I4 megarads.

3 RADIATION SENSITIVITY OF E. COLI Gamma Radiation Dose Percent of E.Coll In general, a sewage plant using fission byproduct waste fortreatment is designed in the manner of conventional plants; for example,a sewage is first directed into a settling basin and preliminarytreatment is given; then, instead of ding sewage into a chlorinationsection, as is presently done, the sewage goes through the radiationsection. The radiation section is formed by putting together a series ofcells described below, and the total number and size of the cells aredependent upon the extent and type of pollution of the input and thedegree of sterilization and chemical breakdown desired. At the presenttime, chlorination is provided for only a few months of the year in somelocations, whereas radiation could be provided all year around just asconveniently and at no additional cost.

FIG. 1 shows an elevational view of radiation cell which has a source ofradiation 11 comprised of a series of leach-resistantfission-byproduct-impregnated bricks in this instance. The bricks areheld in a source holder 14 having a number of openings 15 for passage ofcoolant through the holder. The bottom of the source holder has a baseplate 12 to support the bricks, and there are bottom guides 13 to locatethe source holder with respect to the outer casing 8. The outer casingcould be made from a wide variety of metals or plastics. The level ofthe water in the radiation cell is shown at 17 and is generally belowthe level of the sewage when the cells are in position or irradiatingthe sewage. Since the pressure difference across the outer casing isvery small, strength of the casing material is not a difficult problemas occurs with cladding of nuclear fuels.

FIG. 2 shows a cross-sectional view of the cell of FIG. I. Here thesource elements 11 are shown surrounded by the coolant 19 (preferablywater), and there are an adequate number of water openings 15 in theholder 14 to permit the free flow of water on all sides of the sourceholder to cool the source. Note that the vertical ends of the holder 14separate the up flow (being heated by the source 11) from the down flow(being cooled by the outside sewage), thus forming a very efficientconvection cell (see also FIG. 3). The coolant flow direction isindicated by the arrows.

FIG. 3 shows a top plan view of the radiation cell with the source andthe outer casing. It will be noted that the source 11 is surrounded onall sides by outer casing 18, and there are bottom guides for the sourceas shown at 13. The casing is generally of interlocking design withcomplementary interlocking grooves shown at 24 and 24a so that a numberof cells may be easily used in combination. However, individual cellsmay be removed and replaced at any time without moving the remainingcells. Across the top of each cell is a cap to prevent contamination ofthe cell contents. These caps ate not shown in the figures.

FIG. 4 shows an alternate embodiment of the cell 32 wherein theleach-resistant fission-product-impregnated source is in the form ofbeads, balls or pebbles arranged in the nature of a packed column. Inthis instance, we show the source at 26, a perforated base plate at 27to support the beads or pebbles, and the cooling liquid flow path at 28,which is upwardly through the material, outwardly through openings 30,and downwardly between the outer casing and the ends of the sourceholder 29. The source holder 29 may have mesh, perforated or similarsides, or there may be no sides at all, but the holder ends shouldextend from one side of the casing to the other so as to separate the upand down flows. The level of the coolant, preferably water, is shown at31. Other details in the source holder in this design are comparablewith, and reference is made to, FIG. 1 to 3 for details not shown inthis figure.

While the design of the source and the source holder are important, onehas a great amount of freedom in that the glasslike material may bemanufactured in any preferred shape or size. Of particular interest is adesign using a source in the form of small glass beads or balls orsource made up of bricklike pieces, stacked one above the other, in aholder to form a large sheet. These two versions are shown in FIGs. Iand 4, respectively. Other forms such as rods, large sheets, ribbons,etc., may also be used, but the preferred form is the glass ball systemwhich lends itself to fluid handling in that the glass beads may bepumped into a suitable lead-lined tank for replacement of sourcematerial. The individual source holder is designed so to provide acooling of the source as well as radiation to the sewage.

Cooling of the system is an important consideration. Fission productwastes are primarily beta emitters, and since beta rays travel veryshort distances in matter, most of their energy is dissipated in thesource element itself. This energy which is dissipated is great (as highas about 0.50 watts per cubic centimeter of source material) and cancause considerable temperature rises in the source. Unless the system isadequately designed, one would obtain boiling and, possibly,volatilization of the source, and in addition the production of veryhazardous dispersion of radioactive material. Each of the radiationcells must be designed to have adequate cooling by natural convectionwithin the cell. The design shown in FIG. I to 4 forms very efficientconvection cells because of the separation of the up and down flows, andalso the cells can be made thin so that most of the gamma radiationescapes the cells and is absorbed in the sewage. Thus, the cells arevery efficient, leading to low cost of the overall system. Note thatwith suitable design of the cells, overheating will not occur, even ifthere is no flow of the sewage.

The radiation source and its coolants are separated from the sewage toreduce the probability of causing contamination the effluent withradioactive material. Even if the source material should crack or breakfor some reason or another, the water or other fluid rnedium could beremoved from the cell and replaced with a noncontaminated material. Onthe other hand, if the casing of the cell should leak, the sewage mayenter the cell and/or the water or other liquid from the cell may enterthe sewage. Unless there had previously been a leak between the sourcematerial and the fluid in the radiation cell, there would be noappreciable damage done. In this regard, it should be noted that thesource is contained by an insoluble leach-resistant material and thecooling fluid should not contain any radioactive material. In any event,any leak between the cell and the sewage is easily detected by initiallyhaving the coolant level different from that of the sewage and thenmonitoring the level of the column of coolant above the source. If aleak occurs, the coolant level will change.

A further feature of the design provides for a column of water above theradioactive material as high as is necessary to provide adequateshielding of the source material.

The sewage treatment apparatus could be designed in such a way that thecell would be completely enclosed in concrete, ut for ease of handlingand at the lowest cost, the sewage would be treated in a longcement-lined tank with the cells parallel to each other in the tank andthey would be exposed to the atmosphere or in a covered building; butwith a substantial amount of water above the cells that would reduce theradiation hazard.

As mentioned, our preferred technique for employing fission byproductwastes as a radiation source is to incorporate them into aleach-reisistant glasslike material such as nepheline syenite. Asalready mentioned, the ultimate source may be in the form of beads,pebbles, bricks, sheets, etc., depending upon other designconsiderations of the system. While it is preferred to impregnate asolid such as glass, it is possible to use such other materials asceramics, metal, porcelain, or any one of many different solids. It isessential, however, that the material be leach-resistant to reduce thepossibility of removing any radioactive material from the source.

As a specific example, it has been found that, a suitable source can beprepared by heating to approximately 1350 C. a mixture of about 50percent nepheline syenite and about 50 percent calcium hydroxide with aconcentrated fission byproduct solution. One kg. of such a material canhold almost 1 litre of concentrated fission waste solution. It has beenfound that leaching losses from this product are less than 5X10 grams ofglass per square centimeter of area per day under normal flow rates.

As a further typical example, a material has effectively been employedconsisting essentially of 1.87 kg. of nepheline syenite, 0.44 kg. ofcalcium hydroxide, and 0.2 litres of water, with 2.2 litres of fissionbyproduct waste which is pelletized and fired in the manner mentioned inthe Watson et al. reference mentioned supra.

While the foregoing has been given as a specific example, it is to beunderstood that numerous other leach-resistant materials may beeffectively utilized. A typical mixture of fission byproduct wastesstored for 5 years after removal from the reactor will contain between30 and 170 curies of activity per litre. Before using this material forthe purposes of this invention, it is concentrated by evaporation to anestimated activity of 20,000 to 50,000 curies per litre.

COMPOSITION OF FISSION PRODUCT LIQUOR FIVE YEARS AFTER REMOVAL FROMREACTOR Aged fission byproduct waste should be used since most of theinitial short lived radioactivity will be eliminated and cooling of thecell is then less of a problem. The cells will also have a long usefullife.

The actual amount of isotopes needed to perform the treatment of sewagedepends upon the amount of sterilization and the amount of chemicalcompound breakdown desired. With a criteria of 100 percent destructionof all synthetic detergents (syndets), 100 percent reduction of thebiological oxygen demand (B.O.D.), and 99.99 percent kill of all E. Colibacteria, we find that approximately 10 curies of fission productactivity is required to treat 100 million gallons of sewage per da In asewage treatment plant, the most convenient construction is to arrangethe cells into rows forming long channels. If the width of the channelis large, the radiation intensity at the center of the channel is weakbut all the radiation is adsorbed in the sewage. If the channel is toothin, much of the radiation is adsorbed in the cells and is thusinefficient.

FIG. 8 shows the relative radiation intensity from a uniform planesource. It may be seen that for a channel width of 5 inches, at least 90percent of the radiation emanating from a cell is adsorbed in thesewage. The amount of radioactive material needed is dependent upon thechannel width, the

source thickness, the amount of material interposed between the sourceand the sewage channel, the number of channels, the size of channels,the sewage flow rate and the degree of treatment required.

The foregoing discussions have related primarily to the principles ofthis invention, the nature of the fission byproduct source, and theconstruction of an individual cell. Referring more particularly to FIGS.5-7, there is shown an exemplary system comprising rows of interlockedcells, arranged in a manner to obtain the necessary flow patterns formixing and uniform irradiation of the sewage without undue pumpinglosses.

FIG. 5 shows a vertical cross-sectional view of a system comprising fivespaced, generally parallel rows of radiation cells with associated guidevanes, 35 and 36, in the flow path of the sewage. The cells, comprisinga source and a source holder, are shown at 11.

FIG. 6 is an elevational view of part of a row ofcells with the cellsdepicted as Ila and the associated spacer elements 20 with upper guidevanes 35 and lower guide vanes 36. A number of cells may be insertedbetween spacer elements. Approximate streamlines are indicated byarrows.

FIG. 7 is a cross-sectional view of the system shown in FIG. 6.

From FIGS. 5, 6 and 7, it is clear that the purpose of the guide vanesis to provide a generally helical flow and mixing around the rows ofcells. This type of flow is provided to ensure uniform irradiation ofall sewage particles. For efficient operation, some such mixing isnecessary since the radiation intensity at different points variesenormously. For example, the radiation intensity at the surface of thesewage is extremely low since the sewage shields the surroundings fromthe radiation. Thus, surface sewage must be in continual motion towardsthe source; otherwise, highly nonuniform irradiation of the sewage willresult. Various other vane arrangements may be made to accomplishuniform mixing, but the advantage of the one shown in FIGS. 5-7 is thatit is simple, effective and has low flow resistance. Note that if theflow in one channel is generally upwards, the flow in adjacent channelsis generally downward.

The same generally helical flow may be obtained by a variety of methods.An alternative to the guide vanes at the top and bottom of the spacingelements is shown in FIG. 9 and 10 In this case, short airfoil-likeblades or vanes project more or less horizontally from the sides of thechannels. In FIG. 9, the vanes I00 are shown projecting from FIGS. sidesof the spacing elements 20, but they could also project from the sidesof the radiation cells 11a. Note that if the vanes on one side of a roware imparting a downward motion on the sewage, as occurs for the vanes100, then the vanes 101 on the other side of the row should impart anupward motion if the flow is to have a generally helical motion around arow. Thus, vanes on opposite sides of a row have opposite angles ofinclination whereas vanes on opposite sides of a channel have the sameinclination. This arrangement gives flows in channels which altematebetween being generally upward and generally downward, as required forhelical flow around the rows. These horizontally projecting vanes mayalso be used in combination with the top and bottom vanes shown in FIGS.6 and 7. Another alternative guide vane arrangement is shown in figs.11, I2 and 13. Here, the cells are separated by vanes (directional) onthe bottom at 202 on the top. Alternate rows of vanes on the bottom arefaced in opposite directions.

Instead of he parallel rows of cells shown in FIGS. 6, 7, 9 and 10, theradiation cells may be arranged to form spiral channels. The type ofguide vanes previously described could be used again. For best results,the spiral channel should be made of two separate spiral rows, one rowwithout any openings so that no sewage could fiow through the row, andthe other spiral row with openings to circulate the sewage from achannel on one side of the row to the channel on the other side of therow.

As previously stated, the gamma radiation causes suspended particles toagglomerate and settle towards the bottom of the tanks. The channel maybe cleaned of deposits very simply, however, by moving one or more pairsof high velocity water jets between the rows of cells. The general flowwould carry suspended particles into settling tanks downstream of theirradiation section.

Many apparently widely different embodiments of this invention may bemade without departing from the spirit and scope thereof, and it is tobe understood that we do not intend to be limited by the specificembodiments disclosed except as defined by the appended claims.

1. A method of treating contaminated water to kill bacteria and degradechemical compounds, comprising:

enclosing a gamma radiation source comprising fission product waste;

passing the source and the contaminated water with respect to each otherto expose the water to the radiation in order to sterilize and killbacteria in the water; the fission product waste being encapsulated in aleach-resistant glass or ceramic product to form a radiation source, theradiation source being substantially below the level of be contaminatedwater so that adequate shielding is provided. 2. The method of claim 1in which the gamma radiation is substantially that of the cesium-bariumisotope.

3. The method of claim 1 in which the fission product waste is held in acontainer with coolant.

4. The method of claim 3 in which the source and the container form anatural convection cell.

5. The method of claim 4 in which the up and down flows of theconvection current are essentially separated by the construction of thecontainer.

6. The method of claim 3 in which the containers are arranged inchannels and the sewage or contaminated water flows along the channels.

7. The method of claim 1 in which the radiation source is in the form ofbeads or balls.

8. The method of claim 1 in which the radiation source is in the form ofbricks.

9. A method or the radiation treatment of sewage to kill a highproportion of the Escherichia Coli bacteria present and degrade chemicalcompounds, comprising:

providing a plurality of gamma radiation sources in spaced relationshipwith channels therebetween and substantially parallel to each other inthe direction of the sewage flow;

providing a flow-diverting means to divert the sewage to an adjoiningchannel whereby a portion of the sewage is diverted to an adjacentchannel thereby to enhance thorough mixing so that equal dosages ofgamma radiation will radiate throughout the sewage to kill theEscherichia Coli bacteria therein.

10. A method for the radiation treatment of sewage to kill a highproportion of the Escherichia Coli bacteria present and degrade chemicalcompounds, comprising:

providing a plurality of gamma radiation sources in spaced relationshipwith channels therebetween and substantially parallel to each other inthe direction of the sewage flow; providing a flow-diverting meansassociated with said radiation source to divert sewage downwardly in onechannel and upwardly in an adjacent channel thereby producing a helicalflow of contaminated water around the source.

11. A radiation cell, comprising:

a source of gamma radiation impregnated in a leach-resistant ceramiclikematerial;

a holder for said source having a low attenuation to gamma radiation;

a low attenuation cooling fluid surrounding said radiation source on allsides; and a liquid-impervious enclosure for said radiation source,holder, and fluid providing for low attenuation of gamma radiation. 12.The radiation cell ofclaim H in which the source holder has openingsabove and below the source and a channel providing fluid communicationfrom the upper to the lower portions of said cell whereby naturalconvection currents of warmed fluid will rise in said source holder andpass outwardly through the openings above the source into the channeland then downwardly in a circulatory manner.

13. A sewage treatment apparatus for exposing bacterial and chemicalcompound-contaminated sewage to irradiation, comprising:

a tank for containing the sewage and having inlet and outlet means;

a plurality of spaced substantially parallel radiation cells in saidtank forming channels therebetween;

each of said cells having its radiation source substantially below theupper level of sewage in the tank;

a series of impervious baffles extending between the source members andfrom a point below the upper level of the radiation cells to a pointabove the bottom of the tank; a plurality of angled vanes at the bottomof the tank beneath the radiation cells, said vanes being formed in rowsand alternating with respect to each other whereby a flow ofcontaminated sewage in the tank flows from one channel over the bafflesat the top of the tank and flows downwardly to the vanes at the bottomof the tank to adjacent channels in a helical pattern whereby the vanesat the bottom create a pressure differential in the channel where thevanes at the bottom are angled toward one another in the direction offlow, resulting in a higher pressure, consequently sewage will flow atthe top of that same channel to adjacent channels because of thepressure differential.

14. A sewage treatment apparatus for exposing bacterial and chemicalcompound-contaminated sewage to irradiation, comprising:

a tank for containing the sewage and having inlet and outlet means;

a plurality of spaced substantially parallel radiation cells in saidtank forming channels therebetween;

each of said cells having its radiation source substantially below theupper level of sewage in the tank;

a series of at least one upper and one lower vane means disposed betweensaid radiation cells and projecting at an incline into the channelsdefined thereby, said vane means comprising flow restrictors andopenings between the rows of cells whereby the flow of sewage alongsubstantially parallel paths will be restricted and will pass to anadjacent channel to provide substantially equal radiation treatment tothe sewage in the tank;

an opening adjacent to each vane providing fluid communication betweenthe channel into which the vane projects and the channel adjacentthereto;

each vane of a given series being inclined in the same direction;

the vanes of the said one series being divergent with respect to thevane of the other series and vanes of one series being verticallydisposed with respect to the vanes of the other series, wherebyapproaching sewage will be diverted from the channel into which the vaneprojects through said opening into the channel adjacent thereto and thenin a direction which includes a vertical com ponent, in a generallyhelical manner.

1. A method of treating contaminated water to kill bacteria and degradechemical compounds, comprising: enclosing a gamma radiation sourcecomprising fission product waste; passing the source and thecontaminated water with respect to each other to expose the water to theradiation in order to sterilize and kill bacteria in the water; thefission product waste being encapsulated in a leachresistant glass orceramic product to form a radiation source, the radiation source beingsubstantially below the level of the contaminated water so that adequateshielding is provided.
 2. The method of claim 1 in which the gammaradiation is substantially that of the cesium-barium isotope.
 3. Themethod of claim 1 in which the fission product waste is held in acontainer with coolant.
 4. The method of claim 3 in which the source andthe container form a natural convection cell.
 5. The method of claim 4in which the up and down flows of the convection current are essentiallyseparated by the construction of the container.
 6. The method of claim 3in which the containers are arranged in channels and the sewage orcontaminated water flows along the channels.
 7. The method of claim 1 inwhich the radiation source is in the form of beads or balls.
 8. Themethod of claim 1 in which the radiation source is in the form ofbricks.
 9. A method for the radiation treatment of sewage to kill a highproportion of the Escherichia Coli bacteria present and degrade chemicalcompounds, comprising: providing a plurality of gamma radiation sourcesin spaced relationship with channels therebetween and substantiallyparallel to each other in the direction of the sewage flow; providing aflow-diverting means to divert the sewage to an adjoining channelwhereby a portion of the sewage is diverted to an adjacent channelthereby to enhance thorough mixing so that equal dosages of gammaradiation will radiate throughout the sewage to kill the EscherichiaColi bacteria therein.
 10. A method for the radiation treatment ofsewage to kill a high proportion of the Escherichia Coli bacteriapresent and degrade chemical compounds, comprising: providing aplurality of gamma radiation sources in spaced relationship withchannels therebetween and substantially parallel to each other in thedirection of the sewage flow; providing a flow-diverting meansassociated with said radiation source to divert sewage downwardly in onechannel and upwardly in an adjacent channel thereby producing a helicalflow of contaminated water around the source.
 11. A radiation cell,comprising: a source of gamma radiation impregnated in a leach-resistantceramiclike material; a holder for said source having a low attenuationto gamma radiation; a low attenuation cooling fluid surrounding saidradiation source on all sides; and a liquid-impervious enclosure forsaid radiation source, holder, and fluid providing for low attenuationof gamma radiation.
 12. The radiation cell of claim 11 in which thesource holder has openings above and below the source and a channelproviding fluid communication from the upper to the lower portions ofsaid cell whereby natural convection currents of warmed fluid will risein said source holder and pass outwardly through the openings above thesource into the channel and then downwardly in a circulatory manner. 13.A sewage treatment apparatus for exposing bacterial and chemicalcompound-contaminated sewage to irradiation, comprising: a tank forcontaining the sewage and having inlet and outlet means; a plurality ofspaced substantially parallel radiation cells in said tank formingchannels therebetween; each of said cells having its radiation sourcesubstantially below the upper level of sewage in the tank; a series ofimpervious baffles extending between the source meMbers and from a pointbelow the upper level of the radiation cells to a point above the bottomof the tank; a plurality of angled vanes at the bottom of the tankbeneath the radiation cells, said vanes being formed in rows andalternating with respect to each other whereby a flow of contaminatedsewage in the tank flows from one channel over the baffles at the top ofthe tank and flows downwardly to the vanes at the bottom of the tank toadjacent channels in a helical pattern whereby the vanes at the bottomcreate a pressure differential in the channel where the vanes at thebottom are angled toward one another in the direction of flow, resultingin a higher pressure, consequently sewage will flow at the top of thatsame channel to adjacent channels because of the pressure differential.14. A sewage treatment apparatus for exposing bacterial and chemicalcompound-contaminated sewage to irradiation, comprising: a tank forcontaining the sewage and having inlet and outlet means; a plurality ofspaced substantially parallel radiation cells in said tank formingchannels therebetween; each of said cells having its radiation sourcesubstantially below the upper level of sewage in the tank; a series ofat least one upper and one lower vane means disposed between saidradiation cells and projecting at an incline into the channels definedthereby, said vane means comprising flow restrictors and openingsbetween the rows of cells whereby the flow of sewage along substantiallyparallel paths will be restricted and will pass to an adjacent channelto provide substantially equal radiation treatment to the sewage in thetank; an opening adjacent to each vane providing fluid communicationbetween the channel into which the vane projects and the channeladjacent thereto; each vane of a given series being inclined in the samedirection; the vanes of the said one series being divergent with respectto the vane of the other series and vanes of one series being verticallydisposed with respect to the vanes of the other series, wherebyapproaching sewage will be diverted from the channel into which the vaneprojects through said opening into the channel adjacent thereto and thenin a direction which includes a vertical component, in a generallyhelical manner.